Fluid control valves of the ball-type are widely used where it is necessary to control the flow of a fluid in a passage. Prior ball-type fluid control valves include a control element which is ball-shaped and which is movable by an actuator between open and closed positions. In the closed position, a curved surface of the control element engages a circumferential seal in the passage to prevent the flow of fluid. In the open position, a fluid path past the control element is aligned with the fluid passage so that fluid flow can take place.
In past ball-type valves, a fluid passage is defined by an inner surface of the rounded portion and inner surfaces of a pair of ears which are joined to the rounded portion. The inner surfaces of the ears are disposed on opposing sides of the inner surface of the rounded portion and comprise substantially flat, parallel walls. These surfaces thus define a fluid passage of substantially constant height. While valves incorporating such a control element have been found to be adequate for most purposes, it would be desirable for a given size valve to increase the flow capacity thereof.